There are numerous types of exercise machines and apparatus for use by individuals who wish to improve their overall physical fitness and strength. Many of the same machines are also used in the medical profession for physical therapy for patients recovering from injury or sickness.
One of the most popular apparatus is free weights which are attached to a bar and lifted in various ways by the person exercising. A disadvantage of free weights is that it can be dangerous to attempt lifting a heavy weight without the use of "spotters". When a person is lifting a heavy weight, "spotters" are required to prevent loss of control of the weight when it is overhead. Without "spotters", the weight can fall causing damage to the exercise area or physical injury to the lifter.
Another type of existing machine exerts a continuous pressure against a range of motion through which the user moves various parts of his body. The disadvantage of this type of machine is the need for many different machines to go through a range of exercises. In addition, these machines do not give the user the "feel" of free weights.
A third type of existing machine is the universal gym type. this type of machine has the same disadvantage as free weights, in that the user can lose control of and drop the weight if he becomes fatigued, causing damage to the machine or injury to himself.
It is desirable in an exercise machine to combine the "feel" of free weights with a safety feature allowing use without "spotters". It would also be desirable to have a machine with an easily adjustable "weight" or pressure to operate.